US3390109A - Alkali stable terpolymer compositions and process for their manufacture - Google Patents

Description

1 O 6 9 Q CROSS REFERENCE EX m //@2 June 25, 1968 A. P. REVERDIN ET AL 3,390,109

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5x4 HPLE l0 A T TUBA/5Y5 United States Patent Office 3,390,109 Patented June 25, 1968 ABSTRACT OF THE DISCLOSURE in R1=H Ol' COORg, R3=H OI CH3, group with 4 to 8 carbon atoms in the proportion between 25 and 50%, a nonionic protective colloid, in the proportion between 2 and 6%, a nonionic surface-active agent in the proportion between 0.1 and 3%, the combined amount of said colloid and said surface-active agent being between 2.5 and 8% of the combined weight of the polymers, and a bufi'ering agent, in the amount of 0.3 to 0.5%, the weight percent of said colloid, said surface-active agent and said buffering agent being based on the weight of the terpolymer. The aqueous resin dispersions are suitable for us inders and binding agen r igments, dyes and fillers.

This invention relates to aqueous dispersions of resins and more specifically to dispersions which are resistant to saponification and which have high binding capacity as dispersing ag'nts.

Resin dispersions find application in many fields, such as pigments and dyes, in connection with hydraulic binding agents, cement products, in the textile industry for textile finishings and in the paper industry, for imparting stiffness to paper. For instance, aqueous resin dispersions are incorporated into building materials, such as concrete, and as binding agents into paint compositions. When incorporated into building materials, which are to remain dry, these dispersions improve the physical properties of the cementitious compositions, mainly the resistance to torsion, stresses, impact, abrasion, and in general the strength, stability and cohesiveness of the compositions. Also, when incorporated into paints, which are used exclusively as interior paints, or only exposed to a dry atmosphere, the paints exhibit improved resistance to cracks, and have greater adhesive stability. On the other hand, the resin dispersions known in the art, are far from satisfactory, when incorporated into outdoor paints, which are exposed to moisture and variable weather conditions.

The main drawback of polyvinyl esters, for instance polyvinyl acetate, is that they'are not'stable to alkali. Dispersions containing polyvinyl esters, as well as the films prepared from them, are fairly easily hydrolized under the action of alkali and water. When dispersions containing a polyvinyl ester, are incorporated into cementitious materials, for instance concrete, or as binding agents for paint formulations, the improvements mentioned above with respect to tenacity, cohesiveness and in general, the physical properties of the cementitious materials, are lost, under the action of water or on exposure to a moist atmosphere. Also, if the paint fomulation is used as a primer coat on a backing which is basic, because of the presence of limestone, for instance concrete, the combined action of the moisture and of the basic material, causes saponification of the polyvinyl acetate present in the paint as binder, with resulting loss of the stability of the paint.

Many efforts have been made to prepare resin dispersions with high binding capacity and stahle t o alkali. Some improvement has been achieved with the dispersions which contain copolymers, for instance vinyl acetatevinyl laurate, vinyl-esters and"'acrylic esters, because of their greater stability to alkali, 'as compared" with the dispersions of polyvinyl acetate. Also these dispersions, however, are not satisfactory as binders for paints, for incorporation into concrete, or into any other basic building material, because they cannot stand frequent, prolonged and strong action of moisture, but are saponified, and the initial improvements in adhesion stability of the paint and of the building material are essentially lost.

Dispersions of copolymers from vinyl chloride and vinyl esters have been investigated for this purpose but have limited application. Although the alkali stability increases with increasing proportion of vinyl chloride, their binding capacity is poor and the resulting building materials and paint formulations have poor cohesion. An-

as additives in concrete materials or as binders in paint formulations of exterior work, is very limited.

One object of this invention is to provide aqueous dispersions of resins which are superior to other disper sions known in the art, for their resistance to saponification and their high binding capacity, for use in hydraulic binders and binding agents for pigments, dyes and fillers. Another object is to provide dispersions which yield films at low temperature, and which are stable at low temperature, even below 0 C. Another object is to provide a process for the preparation of the aqueous resin dispersions of this invention, which is economical and suitable for commercial sale.

These and other objects will appear hereinafter from the description which follows.

The crux of the instant invention resides in the finding that the above-stated advantages may be achieved by preparing the dispersions from terpolymers which comprise between 20 and 40% by weight of component A, which is vinyl chloride, between 20 and 50% by weight of component B, which is a vinyl ester containing between 1 and 3 carbon atoms in the acid radical, and between 25 and 50% by weight of a component C, which has the general formula in which R =H or COOR R =H or CH and R =alkyl group with 4 to 8 carbon atoms.

It is essential, within the scope of this invention, to prepare the terpolymer in water in the presence of a nonionic protective colloid, the latter being used in the amount between 2 and 6% of the combined weight of the monomers, and in the presence of a buffering agent, such as secondary sodium phosphate, to keep the pH of the mixture, at the beginning 'at the polymerization, in the range of 4.5 to 5 and at the end of the polymerization. at 3 or higher.

It is also recommended to add a nonionic surface active agent or emulsifier, in amount between 0.1 and 3% of the combined weight of monomers, and with a catalyst for the polymerization reaction.

In accordance with a preferred embodiment of the invention, the concentration of the vinyl chloride is kept 3 at between 25 and 35%, the concentration of vinyl ester at between 25 and 40%, and the concentration of the protective colloid at between 3 and It is also advantageous to have a plasticizer in the proportion between 2 and 3% by weight of the combined weight of the monomer.

As component B, that is, the vinyl ester, vinyl acetate is preferably used.

As component C, that is, the compound of formula R CH=CR COOR acrylic esters, such as butyl acrylate, may be advantageously used. Also the esters of methacrylic acid or of maleic or fumaric acid, or 2-ethyl is preferably. used.

As a plasticizer, any of the known neutral plasticizers, which are compatible with the resins and act as solvents by maintaining the resins in dispersion, may be used, such as, for instance, dibutyl phthalate, esters of citric acid, neutral phosphoric acid esters, and glycol-ic esters.

As already mentioned above, the polymerization reaction within the scope of the invention, takes place in an aqueous dispersion, and the presence of the protective colloid material is essential. As protective colloid substances, only nonionic water-soluble substances may be used, such as, for instance, polyvinyl alcohol, hydroxymethylcellulose, hydroxyethyl cellulose and poly N- vinylpyrrolidone. Polyvinyl alcohol is very satisfactory.

As nonionic surface active agents or emulsifiers, there may be used the condensation products of ethylene oxide, ethanolamine, or sorbitol with fatty acids, tall oil, alkylphenols, fatty acid amides, and with aliphatic alcohols. Very suitable, within the scope of the invention, is the condensation product of ethylene oxide with nonylphenol, which has an ethylene oxide content of 55 to 65%.

of surface-active agent being kept between 0.1 and 3%.

For the purpose of obtaining the terpolymer in the desirable particle size, it is preferable to prepare first a master latex of polyvinyl ester, that is an emulsion of polyvinyl ester in water, and then to allow the polymerization of the three monomers to-proceed on the preformed latex. Although the solid content of the latex is not crucial, it is preferred to prepare a latex with a solid content of polyvinyl ester of between 5 and calculated on the combined weight of the monomers.

As polymerization catalysts or accelerators, there are used the water soluble catalysts which are known to catalyze free radical reactions, such as, for instance, peroxides and persulfates. Alkalipersulfates are satisfactory. The polymerization reaction is conveniently conducted at a temperature between 60 and 70 C.

For the purpose of better illustrating the invention, the following examples are described in detail hereinbelow.

Example 1 In a stainless steel, double-jacketed, two-liter autoclave, provided with mechanical stirrer, thermometer and feed reservoir, were placed 570 grams of soft water, 30 grams of 100% polyvinyl alcohol, 6 grams of the condensation product of ethylene oxide and nonylphenol, of 63% ethylene oxide content, 1.5 gram of sodium acetate, 3 grams of disodium phosphate, and 2 grams of potassium persulfate. The polyvinyl alcohol had a saponification number of 125-140, and the viscosity of a 4% solution, at C., was -40 centipoises.

The autoclave was closed, flushed with nitrogen and evacuated. Through the feed reservoir, a mixture of 180 grams of vinyl chloride, 180 grams of vinyl acetate, 240 grams of butyl acrylate, and 12 grams of dibutyl phthalate as a plasticizer, was gradually added. After the addition of about 50 grams of the monomer mixture, the autoclave was warmed to 65 to 70 C. under agitation.

The pressure rose to 1.5 atmospheres at 60 C. As soon as polymerization began, at 65 C., a pressure drop was observed. The remainder of the monomer mixture was then added, at such rate that the pressure never rose above 3 atmospheres. The total addition required 4 hours. The reaction mixture was kept under agitation an additional period of 2 hours at 70 C. After blowing air through to remove the last traces of unreacted monomers, the pH was adjusted to 5, by addition of a 5% sodium carbonate solution and the reaction product was cooled.

Example 2 In a stainless steel, double-jacketed, 4000-liter autoclave, provided with anchor-shaped stirrer, thermometer and manometer, were placed 1150 kg. of soft water, 50 kg. of polyvinyl alcohol, 12 kg. of the condensation product of ethylene oxide and nonyl phenol, with 63% ethylene oxide content, 6 kg. of disodium phosphate dodecahydrate (Na I-lPO-12 H 0), and 3 kg. of potassium persulfate. The autoclave was connected with a pressure tank. After flushing the appaartus with nitrogen and evacuating, 60 kg. of vinyl acetate were added for the formation of the polyvinyl acetate latex. The autoclave was then closed and warmed to 6570 C. The pressure at first rose, to about 0.5 atmosphere, at 60 C., then dropped as soon as polymerization began. After the pressure dropped to 0.2 atmosphere, a mixture of 360 kg. of vinyl chloride, 360 kg. vinyl acetate, 480 kg. of butyl acrylate, and 24 kg. of dibutyl phthalate was added, gradually, at such rate that the pressure did not rise about 3.5 to 4 atmospheres. The addition of the monomer mixture was complete in a period of 2 to 3 hours. The reaction mixture was kept one hour longer at 70 C., under agitation, until the pressure dropped to 0.5 atmosphere. After blowing air through to remove the last traces of unreacted monomers, the pH was adjusted to 5 with 5% sodium carbonate solution and the reaction product was cooled.

Example 3 The polymerization of 200 grams of vinyl chloride, 200 grams of vinyl acetate, 200 grams of 2-ethyl l-hexyl acrylate, was carried out in the presence of 6 grams of dibutyl phthalate, as in Example 1, except that a latex of polyvinyl acetate was prepared first, as in Example 2, from 30 grams of vinyl acetate, corresponding to 5% of the combined weight of the monomers.

Example 4 The polymerization was carried out as in Example 3, from a monomer mixture consisting of g. vinyl chloride, 180 g. vinyl acetate, 240 g. of dibutyl maleate and 12 g. of dibutyl phthalate, as a plasticizer.

Example 5 The polymerization was carried out as in Example 3, from a monomer mixture consisting of 154 g. of vinyl chloride, 210 g. vinyl acetate, 236 g. butyl acrylate, and 12 g. of dibutyl phthalate as a plasticizer.

Example 6 The polymerization was conducted under the same conditions as in Example 3, except that instead of polyvinyl alcohol, a total of 18 grams of hydroxyethylcellulose was used. The monomer mixture consisted of 180 grams vinyl chloride, 180 grams vinyl acetate, 240 grams butyl acrylate and 12 grams dibutyl phthalate.

The aqueous resin dispersions containing the terpolymer compositions prepared as described in Examples 1 through 6, were free from clots, and showed no tendency to coagulate. They exhibited remarkable stability to electrolytes, and to storage, even at low temperature, in the range of 10 to -20 C. They exhibited good resistance to alkali, and film formation from the dispersions occurred even at very low temperatures. The dispersions were compatible with hydraulic binding agents, a property necessary for incorporation into cement materials and 1.5 N potassium hydroxide. The amount of potassium concrete. Further, the dispersions prepared as described hydroxide used was determined after each time interval. above, exhibited good binding capacity, a property neces- The results tabulated in Table 1 show the superiority in sary for use as binders in pigments and fillers. The films resistance to saponification of the dispersions prepared in prepared from the dispersions of this invention were su- 5 accordance with this invention in Examples 1 through 6, perior to other films known in the art, for their high tensile as compared particularly with the dispersions of Examples strength and high stretchability, in the order of 300 to 7, 8, that is, pure polyvinylacetate and the dispersions 700%. The films exhibited excellent adhesion characterfrom vinylacetate and 2-ethylhexyl acrylate, which are of istics and high resistance to wet abrasion, both in comlittle value for incorporation into cement compositions bination with pigments and with fillers. When incorporated and paint formulations. into cement mixtures, for instance concrete, the resulting The dispersions prepared from the copolymers of vinyl materials were outstanding for their high resistance to toracetate and vinyl chloride, that is the materials from Exsion, flexure and to compression forces, and resistance to amples 9 and 10, although more stable to alkali, are of the action of moisture. These characteristics were not eslittle use for incorporation into concrete and other cesentially aflected by immersion in water. mentitious materials and as binders in pigments and filler In order to compare the properties of the dispersions of compositions, because of the high temperature of film the terpolymers prepared in accordance with this invenformation, P slretchahihty (1688 than and P tion, with other dispersions known in the art, other discohesiveness. persions were prepared and a series of tests were per- The dispersion prepared from'the copolymers of vinyl formed, as it will be described hereinbelow. Example 7 in pr pi na and acrylic esters, that is Example l1,"e xthe tests which follow, represent the dispersion from one hibits low resistance to tearing, that is the tensile strength single ingredient, that is polyvinylacetate. Example 8 reps only 8- resents the dispersion from vinylacet'ate and 2-e'thylhexyln O e o determine the Suitability of the dislxrsiohs acrylate, in the ratio of 80 to 20% by weight. Example 9 prepared in accordance with this invention, for incorporais the dispersion from vinyl acetate and vinyl chloride, in h into m hydrauliti Cements and utdo r the ratio f to 20% b i ht d E l 10 i a paints, that is, in general in material which is to be exdispersion of vinyl acetate and vinyl chloride in the ratio posed to moisture of the atmosphere and rain, the coof $0 to by weight. hesiveness of plaster and hydraulic cements having a basic The preparation of the dispersions in Examples 7 to 10 composition, under water, was determined. Table 2 gives was conducted according to the procedure described in 30 the results with the dispersions prepared according to this Example 3. Example 11 in the tests is a commercial mventlon, that is Examples 1 through 6, and other;dispreparation of the dispersion from vinyl propionate and persions known in the art, that is Examples 7, 9, l0 ethyl acrylate. Table 1 shows the results of several comand 11. I parative tests between the dispersions of Examples 7 to The test was conducted by mixing one gram of the 11, and the dispersions prepared according to this invencement and 3 grams of sand, of particle size between 0 and tion, Examples 1 through 6. 1 mm., with water and each of the dispersions under TABLE 1 Example No 1 2 a 4 5 0 7 s 0 10 11 Solid content in percent 53 53 54 51 50 50 50 51 50 50 Viscosity in poises (Brookfield viscometer 80-120 145 100 no 240 s5 0.3-3 0.3-30 5-2.5 0.5-2 0.3-2 1.5-2 0.5-3 0.2-2 1-3 13 0. 2-3 Resistancetotreezingln'G ---20 20 20 20 20 20 10to 20 -10 -1O 10 10 Stability to alkali in mgs. of KOH used per a gram of solid material after-- 24hours 30 29 a4 40 30 35 510 465 55 30 62.5 48 Mars... 47.5 48 as 00 so 50 000 500 70 30 105 72l1ours e0 59 a4 74 66 67 000 500 121 30 143 Temperature of film formation in C- 8 9 10 15 4 10 20-25 10 35-60 8 Tensile shength in kgJcmJ, with atmosp"erlc moisture, at 20C 10 140 70 67 350-400 40 250 320 a Stretcability, in percent, with 65% atmospheric moisture, at 20C 650 610 400 330 620 620 10 700 1 1 900 The rate of saponification was determined by placing test, as a 50% dispersion based upon the total solid con- 100 grams of the dispersion under test in a flask, with 500 tent was added- The composllloh was Placed as a y of 2 N otassium h droxide Solution mix, 3 mm. thick, over abacking of glass or roofing material mu u p y 55 for instance known in the trade as Eternit. The amouni i flask and keeping mateflal und er aglta' of the dispersion added was 5% in the case of glass and 1011 at 25 for a Predetermmed Penod of tlme- The 10% in the case of Eternit. After drying in the air for alkali concentration of the material corresponded to three days, the samples were placed under water.

TABLE 2.STABILITY OF HYDRAULIC CEMENTS. CONTAINING DIS- PERSIONS FROM EXAMPLES 1 THROUGH 6, 7, QTHROUGH ll, OVER GLASS AND ETERNIT Cohesion Stability After drying After standing in After standing in water, 24 hours water for 2 months Example 11.

It is manifest from the data of Table 2, that cementitious materials, essentially basic because of the presence of limestone, are stable, even for a period of two months, under water, if the dispersions prepared in accordance with this invention, are used. On the other hand, the dispersions of Examples 7, 9, and 11 cause the material to be dissolved, even in the course of 24 hours.

Similar results were obtained when the dispersions of the invention were used as binders in paints, pigments and in filler compositions, containing for instance, sand. In each instance, the paints, pigments and filler compositions were not affected and did not go in solution on prolonged standing in water, even on a smooth surface, such as glass or Eternit.

For the purpose of determining the resistance to water corrosion of films containing pigments, several tests were conducted, designed to compare the resistance to water Tests were also conducted to determine the resistance to torsion forces of the hydraulic cements incorporating the dispersions of the invention, as compared with other dispersions known in the art. The tests were conducted by mixing 1 gram of Portland cement and 3 grams of sand, of grade between 0 and 5 mm., with water, adding the resin dispersion, under test, as a dispersion, based upon the total solid content, and forming prisms of dimensions 2 x 4 x 16 mm. The resistance to torsion was determined (1) after a 28-day period standing in the air, of 65% moisture content, (2) after an additional 1-day period standing in water and (3) after an additional 7- day period standing in water. The results in resistance to torsion forces of several hydraulic cements are listed in Table 4. A control of an hydraulic cement, without resin dispersion is also shown.

TABLE 4.RESISTANCE T0 TORSION OF HYDRAULIC CEMENTS CONTAINING RESIN DISPE RSIONS Resistance to Torsion 28-day Dispersion Water to standing in percent cement in an +one day +seven-day by weight factor atmosp ere standing standing of in water in water moisture content Without addition of dispersion 0.44 77 56 l 0.39 70 68 Dispersion according to Example 1 5 0. 36 95 10 0. 37 105 85 Dispersion according to Example 2 5 0. 36 91 60 72 Dispersion according to Example 3..-. 5 0.36 80 40 45 Dispersion according to Example 4-.-. 5 0. 36 37. 5 47 Dispersion according to Example 5.. 5 0. 344 130 80 Dispersion according to Example 6.- 5 0. 47 76. 5 47. 6 80 Dispersion according to Example 7 5 0.41 110 25 10 According to Example 8, with vinyl acetate and Z-ethylhexylacrylate in the ratio of 80 to 20 5 0. 37 62 8 According to Example 11, with vinyl propionate and ethyl acrylate 0. 396 83. 9 35. 4 37. 6

corrosion and binding capacity of the dispersions prepared according to this instant invention, and dispersions known in the art. The tests were conducted by letting a film to form over the base material, Eternit, spraying with a solution of 5% soft soap and 1% sodium carbonate and simultaneously moving a brush back and forth over the surface of the film. Table 3 below, gives the results with the dispersions according to the instant invention, namely Examples 1, 2, 5 and 6, and with the dispersions known in the art, that is Examples 7, 8 and 11.

TABLE 3.RESIS'IANCE TO WATER CORROSION OF FILMS APPLIED AS COATINGS OVER A BASE OF ETERNIT, WITH DIFFERENT RATIO OF PIGMENT T0 BINDER (Determination according to Dr. Oosterle test) Ratio Number of strokes of brush Dispersion of pigment to hinder 4:1 After 5,000, perfect, untouched. According to Examples 1 and 2 6:1 Do.

8:1 After 1,500, corrosion occurs. According to Examples 5 and 6 4:1 After 2, 000, perfect, untouched.

Dispersion from polyvinyl acetate with 12% 4:1 After 920, corrosion occurs. dibutyl phthalate and 8% tricresyl phosphate, according to Example 7. Dispersion prepared according to Example 4:1 After 1,200, corrosion occurs.

8, that is from vin l acetate and Z-ethylhcxylaeryiate, in t e ratio of 80 to 20 Dispersion prepared from vinyl-propionate 4:1 After 5,000, perfect, untouched. and ethyl acrylate, according to Example 6:1 After 2,200, corrosion occurs. 11. 8:1 After 400, corrosion occurs.

Comparison of the results obtained with Examples 1 and 2 with the results from Example 11, clearly shows that the dispersions prepared according to'this instant invention, permit the incorporation of pigment and binder in a higher ratio than with the dispersions known in the art. Manifestly, the binding capacity of the dispersions of the invention is superior to the dispersion, for instance, from vinyl propionate and ethyl acrylate. It is also clear from the results above that the films prepared from the dispersions of the instant invention, have superior resistan e to water corrosion.

The table also gives the results with a sample of hydraulic cement to which no resin dispersion was added, as a control.

TABLE 5.-COMPRESSION STRENGTH OF HYDRAULIC INCORPORATING DIFFERENT RESIN DIS- Compression strength in kg./ern.

Nopoo NXZ is a blend oi mixed hydrocarbons, nonionic emulsifiers, metallic soap and silicone.

Manifestly the results wtih the dispersions according to Examples 1 and 2 show that the hydraulic cements are far more resistant to compression force than the cement incorporating the resin dispersion according to Example 11. Also, the results obtained after a 28-day period standing in water, undisputabiy show the superiority of the resin dispersions prepared according to this instant invention, over the dispersions known in the art.

It may be advantageous, in the incorporation of the resin dispersions intothe cements, to add a small amount of an anti-foaming agent, in an amount between 0.05 and 0.5 by weight.

The dispersions prepared according to this instant invention, because of their high binding capacity, are outstanding as binders for water-proof dyes and for the preparation of friction compositions, for instance for matches, which comprise a dispersion and a filler, such as sand. They are of great value for incorporation into cement compositions, concrete, for the preparation of new special plasters and mortars, and for improving the properties of known concrete, light-weight building compositions, paints and flooring.

In addition, to the above, the dispersions prepared according to this instant invention, find application as substitutes for the dispersions known in the art, and for all other uses of the known dispersions, with plasticizers, pigments and dyes, for instance for the preparation of textile finishings, in the paper industry, floor coverings and seat covers.

, Although only a few applications of the invention have been described in detail, and only a few examples have been set forth for the purpose of greater clarification, those skilled in the art will readily visualize that many other modifications and variations are possible, without departing from the spirit of the invention, which is to be limited only by the scope of the appended claims.

The date of saponification as a function of time for the compositions prepared according to this instant invention and the composition known in the art have been plotted in FIG. 1. The curves for Examples 1 through 6 are strikingly different than the curves for Examples 7 and 8.

What is claimed is:

1. An aqueous resin dispersion, of pH between 3 and 5, resistant to saponification, comprising a lymer from a' component A, which is vinyl chloridejh t epfi portion between and 40%, a component B, which is a vinyl este; with 1 to 3 carbon atoms in the acid radical, in the proportion between 20 and 50%, and a component C, which has the general structure in which R,=H or COOR R2=H or CH R =alkyl group with 4 to 8 carbon atoms, in the proportion between and 50%, a nonionic protective colloid, in the proportion between 2 and 6%, a nonionic surface-active agent in the proportion between 0.1 and 3%, the combined amount of said colloid and said surface-active agent being between 2.5 and 8% of the combined weight of the polymers, and a butfering agent, in the amount of 0.3 to 0.5%, the weight percent of said colloid, said surface-active agent and said buflering agent being based on the weight of the terpolymer.

2. The dispersions according to claim 1, wherein vinyl chloride is in the proportion between 25 and 35%, the component B is in the proportion of 25 to 40%, the pro tective colloid is in the proportion of 3 to 5%, the combined amount of the surface-active agent and of the colloid being between 3.5 and 7% of the weight of the terpolymer, additionally comprising a neutral plasticizer which is compatible with said terpolymer, in amount of 2 to 3% of the weight of the terpolymer.

3. The dispersion according to claim 1, wherein said buffering agent is disodium phosphate in the amount of 0.3 to 0.5% of the weight of the terpolymer.

4. The dispersion according to claim 1 wherein said component B is vinyl acetate, said component C is a member selected from the group consisting of butyl acrylate, 2-ethyl l-hexyl acrylate, esters of r'nethacrylic, maleic, and fumaric acid, and said protective colloid is a nonionic water-soluble substance, selected from the group consisting of polyvinyl alcohol, hydroxymethyl 1celllulose, poly-N-vinyl pyrrolidone and hydroxyethyl celu ose.

5. The dispersion according to claim 2 wherein said plasticizer is a member selected from the group consisting ofdibutyl phthalate, neutral phosphoric acid esters, glycolic esters and citric acid esters.

6. The dispersion according to claim 1 wherein said surface-active agent is a condensation product of a member selected from the group consisting of ethylene oxide, ethanolamine and sorbitol with a member selected from the group consisting of fatty acids, tall oil, alkylphenols, fatty acid amides, and aliphatic alcohols.

7. The dispersion .according to claim 6 wherein said surface-active agent is the condensation product of ethylene oxide and nonyl phenol, which has 55 to 65% ethylene oxide content.

8. The process of preparing an alkali-resistant aqueous dispersion of a terpolymer which comprises the steps of polymerizing between 20 and 40% of a component A, which is vinyl chloride, with 20 to 50% of a component B, which is a vinyl ester with 1 to 3 carbon atoms in the acid radical, and with 25 to 50% of a component C, which has general formula in which R =H or C0OR R =H or CH R =an alkyl group with 4 to 8 carbon atoms in water, in the presence of 2 to 6% by weight of a protective colloid, between 0.1 and 3% of a nonionic surface-active agent, a catalyst of the free radical type, and a buffering agent in amount suflicient to keep the pH at 3 to 5 at the beginning of the polymerization and above 3 at the end thereof, whereby an aqueous dispersion of said terpolymer is formed, adjusting the pH to 5 and cooling said reaction product.

9. The process according to claim 8 wherein a latex of polyvinyl acetate is formed, prior to said step of polymerization.

10. The process according to claim 9 wherein said latex contains between 5 and 10% of polyvinyl acetate.

11. The process according to claim 8 wherein said polymerization is conducted at 60 to 70 C.

12. The process according to claim 8 wherein the pressure is maintained below 4 atmospheres during said polymerization.

13. The method of imparting to hydraulic binding materials high resistance to torsion and stability in water and alkali, which comprises incorporating into said materials between 5 and 10% of a 50% aqueous dispersion 11 which comprises a terpolymer from a component A, which is vinyl chloride, in the proportion between and 40%, a component B, which is a vinyl ester with 1 to 3 carbon atoms in the acid radical, in the proportion between 20 and 50%, and a component C, which has the general structure R1CH=CRQCOOR3 in which R =H or COOR R =H or CH;,, R =alkyl group with 4 to 8 carbon atoms in the proportion between and 50%, a nonionic protective colloid, in the proportion between 2 and 6%, a nonionic surface-active agent in the proportion between 0.1 and 3%, the combined amount of said colloid and said surface-active agent being between 2.5 and 8% of the combined weight of the polymers, and a bufiering agent, in the amount of 0.3 to 0.5 the weight percent of said colloid, said surface-active agent and said buffering agent being based on the weight of the terpolymer.

14. The method according to claim 13 in which an antifoaming agent is added in the proportion of 0.05 and 0.5%.

15. The method of imparting stability to alkali and high cohesiveness to emulsion paint formulations containing pigments, which comprises incorporating into said formulations a binder which is an aqueous dispersion which comprises a terpolymer from component A, which is vinyl chloride, in the proportion between 20 and 40%, a component B, which is a vinyl ester with 1 to 3 carbon atoms in the acid radical, in the proportion between 20 and 50%, and a component C, which has the general structure R1CH=CRQCOOR3 in which R1=H or COOR3, R==H or CH3, R =alkyl group with 4 to 8 carbon atoms in the proportion between 25 and a nanionic protective colloid, in the proportion between 2 and 6%, a nonionic surface-active agent in the proportion between 0.1 and 3%, the combined amount of said colloid and said surface-active agent being between 2.5 and 8% of the combined weight of the polymers, and a buffering agent, in the amount of 0.3 to 0.5%, the weight percent of said colloid, said surface-active agent and said buffering agent being based on the weight of the terpolymer, the proportion of said pigments to said binder being between 4:1 and 8:1.

16. An aqueous resin dispersion essentially consisting of (1) a terpolymer from (A) about 20-40% by weight of vinylehloride, (B) about 20-50% by weight of a vinyl ester with 1-3 carbon atoms in the acid radical, (C) 25-50% by weight of a compound of the formula R CH=CR,-COOR wherein R =H or COOR R =H or CH and, R =alkyl of 4-8 carbon atoms (2) 2-6% by weight, calculated on the amount of the terpolymer, of a nonionic protective colloid (3) 0.5-2% by weight, calculated on the amount of the terpolymer, of a nonionic emulsifier and (4) a pH buffering agent in an amount sufficient to adjust the pH of the dispersion to a value of between about 3-5.

No references cited.

WILLIAM H. SHORT, Primary Examiner.

J. NORRIS, Assistant Examiner.

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